The present invention relates to a paper discharger and an image forming apparatus that are configured so as to perform paper conveying process to a first stacking tray and paper conveying process to a second stacking tray by a driving force from a single motor capable of reversible rotation in both directions.
In an image forming apparatus, paper is conveyed to a stacking tray by a plurality of conveyor rollers. To the plurality of conveyor rollers, driving force is supplied ordinarily by a motor as driving source via a gear train as power transmission mechanism.
Here, among conventional gear trains are those configured so as to be divisible in the middle. For example, for a gear train supplying driving force to the conveyor rollers that are included in a movable unit capable of attachment and detachment, it is necessary to be configured so as to be divisible with the movement of the movable unit.
Then, among the apparatus employing such a gear train that is divisible as stated above, as shown in Japanese Patent Unexamined Publication No. 2007-055706 bulletin, there have been those employing a structure to absorb positional deviation that is attributed to the division, by supporting a gear disposed at the division point with a swingable arm.
In the case where a swingable arm according to the above-mentioned Patent literature is employed, it has been often that direction of the rotation is designed in order that, when the gear supported by the swingable arm rotates together with the other gear engaged therewith, the swingable arm hardly comes apart from the gear.
However, in circumstances where it is required to rotate a gear supported by the swingable arm in both directions, it is unavoidable to rotate the gear supported by the swingable arm in the direction whereby the swingable arm is apt to come apart from the gear engaged therewith. Therefore, the swingable arm has occasionally been likely to shake with the rotation of the supported gear, causing malfunction such as tooth jump of the gear and emission of abnormal sound. Namely, it may be said that in a configuration, for example, so as to convey paper to a plurality of stacking trays by driving force from a single driving source, because it is necessary to change the direction of rotation of a gear train appropriately, the aforementioned malfunction is prone to occur.
In order to get rid of such a deficiency, it is possible to have a configuration in which separate driving forces are provided from separate driving sources for respective sides of a division point of a gear train; however, employing such a configuration would require an additional driving source, thereby resulting in a complicated configuration, and hence an increased cost.
The present invention is directed to providing, with a simple configuration, a paper discharger that is capable of effectively suppressing occurrence of tooth jump at a division point in a gear train, even when the gear train that is divisible is rotated reversibly in both directions, and an image forming apparatus.